Mocha doesn't have a lot of features provided by jest.
There is a great assertion library out of the box.
And the most cool feature is inline snapshots.
Mocha also hides errors which makes debugging a nightmare sometimes.
Ref https://github.com/svg/svgo/issues/1327
Config file now can only be js. `svgo.config.js` is searched by default.
Otherwise any js module specified in `--config` cli flag.
Config loader is exposed in entry point as `loadConfig(configFile, cwd)`.
Ref https://packagephobia.com/result?p=coahttps://packagephobia.com/result?p=commander
Coa was not updated for 2 years already and has outdated dependencies.
In this diff I replaced it with commander which has simpler syntax, none
dependencies and require arguments out of the box. Also array argument
is set syntactically which means more user-friendly "help".
